This invention relates in general to an epoxy resin bonding pad for a ceramic orthodontic appliance, and more particularly to a light-curable methacrylate based epoxy resin bonding pad molded onto a ceramic orthodontic bracket.
Heretofore, it has been known to provide flexible bonding pads for ceramic brackets to facilitate debonding of the bracket or appliance from a tooth without causing damage to the enamel of the tooth and/or breakage of the bracket, as disclosed in U.S. Pat. No. 5,098,288 and 5,263,859.
It has also been known to mold an epoxy resin bonding pad onto a ceramic bracket wherein the epoxy resin is heat-cured. The transmittance of visible light through this bracket and pad is on the order of twenty percent Such bonding pads have textured surfaces for enabling the mechanical adhesive bonding of the bracket and pad to a tooth. This epoxy resin is a two-component system which requires heat-curing.
The present invention relates to an improved epoxy resin for making the bonding pads of ceramic orthodontic appliances such as brackets, wherein the improved resin is used for casting the bonding base onto the ceramic appliance. The bonding pad of the invention is formed from a light-curable resin that contains a metallic oxide and results in a better match of tooth color and improved bond strength.
The improved resin is acrylic based and is compounded with suitable monomers and light-curing catalysts, together with a metal oxide pigment. Accordingly, the improved resin according to the invention, when cast or molded onto a ceramic orthodontic appliance is light cured.
The light-cured resin cast bonding pad of the invention enables the mechanical bonding of the bracket to a tooth and which can be debonded without use of special tools, without damaging the tooth enamel, and without causing breakage of the ceramic bracket. Debonding is performed by squeezing the pad with ligature cutters causing the bracket to release from the tooth.
It is therefore an object of the present invention to provide a new and improved acrylic based epoxy resin for casting bonding pads onto ceramic orthodontic appliances.
A further object of the present invention is to provide a new and improved bonding pad or base for orthodontic ceramic appliances which increases the bond strength and more closely matches the tooth color by decreasing the transmittance of visible light through the bracket and pad.
A still further object of the present invention is to provide an improved epoxy resin for casting bonding pads onto orthodontic ceramic brackets that is light-curable.
Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts.